1. File Sizes & Types

2. Size Matters

3. Kilobytes (K) 1024 bytes = 1 kilobyte— a tiny trademark graphic or log might be a few kilobytes in size, whereas a full web page might be 35- 100 kilobytes. Anything beyond 100K will probably require significant download times for people with dialup modems. Word docs are usually under 1000K, even with images. 10K

4. Megabytes (MB) (This PPT presentation is just under 1MB) 1024KB = 1MB (megabyte)—Most email servers have maximum of 2MB you can send. PowerPoint presentations get this big because of images. About 10-20 web pages would take up 1MB. Web hosting sites sell server space in terms of megabytes. My web site has more than 2000 files, and I have still not reached my 150 MB capacity (but we’re getting close).

5. Gigabytes (GB) 1024MB = 1GB (gigabyte). Rarely do we see single files that are in the gigabyte range. Usually you will see the term gigabyte to indicate hard drive space.

6. Terabytes 1024GB = Terabyte

7. File Formats

8. Common For Web JPEG GIF

9. Original.jpg dithered.jpg gif 8 colors gif 4 colors “When Good Photos Get Saved Badly”

10. How should this have been saved: jpg or gif? How was it saved instead?

11. Extension FormatUsed for`Loss`# ColorsTransparency?.jpg Joint Photographic Experts Group Continuous tone (e.g., photos) Web LossyThousands NO.gif Graphic Interchange Format (Compuserve) Solid colors (e.g., cartoons) Web Loss less 256 + transpa rency Yes, GIF-8 (jaggies).png Portable Network Graphics format Web (continuous tone or solid colors) Lossless Thousa nds Yes (no jaggieds) but big file.tif Tagged Image File Format Print Only LosslessThousandsYes File Formats

12. Transparency: gifs & pngs for web

13. “The dreaded white jaggies”

14. White jaggies are undetectable on white background, but that defeats the purpose of transparency for use with any colored background. Solution: Use a 24-bit png

15. Quiz Yourself: How would you save this? Photo of your sister on the web Black and White logo on the web without transparency Black and white logo with transparency Image for National Geographic

16. Compression Zip files Jpegs Tifs Compress ONCE Cannot uncompress Jpegs and Gifs or add quality that is lost.

17. Dots Per Inch (dpi) 72 dpi standard for web 85-150 dpi low quality print 200 dpi starting point for decent print 300 dpi pretty strong Goes up to 2,000 dpi for highest quality on average scanners (creates enormous files)

18. Questions?